Module MK40 Setup Manual
ВШПА.421412.304 И1
Parameters measurement
MK40 Module operates in real-time mode with measurement results update rate of 250ms.
Module implements the following basic operations:
•
measures sensor current and monitors sensor functionality;
•
measures rotor speed;
•
repeats tachometric pulses for control modules synchronization, calculating variable signals (only for
“slot” reference surface);
•
compares calculated parameter values with set-points and signals overrun;
•
transfers measured values to standard outputs;
•
generates logic alarms;
•
updates data on display equipment;
•
supports data exchange via digital communication interfaces.
At measuring channels outputs resettable fuses and protective stabilitrons (triacs) are provided, which prevent
damage to module input circuits, caused by impulse interference or hazardous voltage level.
Both measuring channels function equally, synchronously and independently of one another. Only several
parameters are common (for detailed description of parameters, refer to Table 16):
•
PeriodMeasur - otor speed measurement period from 0.1 to 1.0 second;
•
TestPointSenseOk - set-points test timeout after sensor function normalization;
•
TimeOut_TestMode - “Measuring channel test” mode timeout;
•
TimeOut_TestStop - “STOP” mode test timeout;
•
SynhroPulse - pulse time of control modules measurements synchronization.
Sensor current measurement
Input current signal must be converted into voltage. For this purpose, precision resistors, corresponding to
sensor signal current range and removable bridge are provided at measurement channels input circuits. Input signals
range by voltage is from 0 to 5V.
Note. During measuring channel function operation with voltage signals, it is recommended to keep margin of
valid signal range in order to implement sensor functionality test function.
Input signal (voltage) passes through low-frequency filter (LFF) and arrives at 10-digit analog-digital convertor
(ADC) input, built in microcontroller. Within 250ms 521samplings of ADC values are implemented in each measuring
channel. ADC mean value is used in further calculations of sensor current. High number of ADC samplings permits to
achieve ADC actual DC resolution of 12bit due to averaging.
Sensor current is calculated by formula:
I
sense
= A
I
+ B
I
⋅ ADC
where
I
sense
– calculated value of sensor current;
ADC – averaged ADC value;
A
I
, B
I
– linear equation ratios for sensor current calculation.
Sensor current value I
sense
can be displayed (by pressing “Curr sense” key) and is used in sensor test algorithm
for calculation of changing parameter value.
A
I
, B
I
ratios are automatically calculated during module operation initialization by sensor current range data
(20% of RangeCurrMax, RangeCurrMax) and saved ADC values (AdcInMin, AdcInMax), corresponding to
sensor current input range, by which calibration has been carried out.
Note. If one of calibration value pairs (20% of RangeCurrMax, RangeCurrMax or AdcInMin, AdcInMax) is
equal to zero, or they are equal, then A
I
, B
I
ratios are not calculated and taken equal to zero (sensor current value I
sense
is always equal to zero).
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